NorFlash初始化为什么会导致PRD函数失效？

硬件：EVM5515

IDE：CCS6.0

软件系统：DSP/BIOS

硬件使用了SDRAM和NorFlash；软件中配置了两个PRD，周期分别是10ms和1000ms。

SDRAM和NorFlash初始化代码如下：

	SDRAM_init();
	CSL_sdramPolledTest();
	nor_flash_init(); // NorFlash初始化
	// NorFlash读写测试=====================================
//	norflash_read(0x00000, (Uint16*)fs_win, 512);
//	norflash_read(0x40000, (Uint16*)fs_win, 512);
//	nor_flash_erase_Block4();
//	norflash_read(0x40000, (Uint16*)fs_win, 512);
//	norflash_read(0x00000, (Uint16*)fs_win, 512);
//	norflash_write(0x40000, (Uint16*)fs_win, 512);
//	norflash_read(0x40000, (Uint16*)fs_win, 512);

SDRAM初始化函数参考了EVM5515官方例程CSL_EMIF_SDRAM_PollExample_Out。

CSL_Status  SDRAM_init(void)
{
	CSL_EmifHandle          hEmif;
	CSL_EmifObj             emifObj;
	CSL_SdramCfg            sdramCfg;
	CSL_SdramTimr           sdramTimr;
    CSL_SdramRowSize        rowSize;
	CSL_Status              status;
	CSL_Status              result;

	result  = CSL_TEST_FAILED;
	hEmif   = &emifObj;
	rowSize = CSL_SDRAM_ROW_ADDR_BITS_12;

	//printf("SDRAM Polled mode test\n\n");

	/* Initialize Emif module */
	status = EMIF_init(&emifObj);
	if(status != CSL_SOK)
	{
		//printf("EMIF SDRAM Init Failed!!\n");
		return(result);
	}

	/* Assign values to sdram config structure */
    sdramCfg.NM           = CSL_SDRAM_SDCR1_NM_DEFAULT;
	sdramCfg.CasLatency   = CSL_SDRAM_SDCR1_CL_DEFAULT;
	sdramCfg.bit11to9Lock = CSL_SDRAM_SDCR1_BIT_11_9_LOCK_DEFAULT;
	sdramCfg.ibankPos     = CSL_SDRAM_SDCR1_IBANK_DEFAULT;
	sdramCfg.ebank        = CSL_SDRAM_SDCR1_EBANK_DEFAULT;
	sdramCfg.pageSize     = CSL_SDRAM_SDCR1_PAGESIZE_DEFAULT;
	sdramCfg.selfRefresh  = CSL_SDRAM_SDCR2_SR_DEFAULT;
	sdramCfg.pdMode       = CSL_SDRAM_SDCR2_PD_DEFAULT;
	sdramCfg.pdwr         = CSL_SDRAM_SDCR2_PDWR_DEFAULT;
	sdramCfg.pasr         = CSL_SDRAM_SDCR2_PASR_DEFAULT;
	sdramCfg.rowSize      = rowSize;
	sdramCfg.ibankPos     = CSL_SDRAM_SDCR2_IBANK_POS_DEFAULT;
	sdramCfg.sdramDrive   = CSL_SDRAM_SDCR2_SDRAM_DRIVE_DEFAULT;
	sdramCfg.bit9to1Lock  = CSL_SDRAM_SDCR2_BIT_9_1_LOCK_DEFAULT;

    sdramTimr.tRAS        = CSL_SDRAM_TRAS_VAL;
    sdramTimr.tRC         = CSL_SDRAM_TRC_VAL;
	sdramTimr.tRRD        = CSL_SDRAM_TRRD_VAL;
	sdramTimr.tRFC        = CSL_SDRAM_TRFC_VAL;
	sdramTimr.tRP         = CSL_SDRAM_TRP_VAL;
	sdramTimr.tRCD        = CSL_SDRAM_TRCD_VAL;
	sdramTimr.tWR         = CSL_SDRAM_TWR_VAL;
	sdramTimr.tXS         = CSL_SDRAM_TXS_VAL;
    sdramTimr.refRate     = CSL_SDRAM_REFRATE_VAL;


	/* Configure SDRAM settings */
	status = SDRAM_config(hEmif, &sdramCfg, &sdramTimr);
	if(status != CSL_SOK)
	{
		//printf("EMIF SDRAM Config Failed!!\n");
		return(result);
	}

	return(result);
}

NorFlash初始化函数参考了EVM5515官方例程CSL_EMIF_NOR_CpuTransfer。

CSL_Status nor_flash_init(void)
{
	CSL_Status 			status;
	status 				= CSL_SOK;
	hNor 				= &norObj;
	norCfg.asyncWaitCfg	= &norAsyncWaitCfg;
	norCfg.asyncCfg		= &norAsyncCfg;

	status = NOR_setup(&norObj, 0);
	if(CSL_SOK != status)
	{
		printf("SETUP: Bad Status\n");
	}

	status = NOR_emifResetAndClock(hNor);
	if(CSL_SOK != status)
	{
		printf("NOR EMIF RST & CLK: Bad Status\n");
	}

	/*norCfg was filled when it was defined*/
	status = NOR_setupEmifChipSelect(hNor, &norCfg);
	if(CSL_SOK != status)
	{
		printf("SETUP EMIF CS: Bad Status\n");
	}

	memset(hNor->deviceID, 0x0, sizeof(hNor->deviceID));
	status = NOR_readId(hNor);
	if(CSL_SOK != status)
	{
		printf("READ ID: Bad Status\n");
	}

	if((0xFF == hNor->deviceID[1]) || (0xFFFF == hNor->deviceID[1]))
	{
		printf("No Device Found\n");
	}
	else
	{
		printf("Manufacturer ID %x\n", hNor->deviceID[0]);
		printf("Device ID %x\n", hNor->deviceID[1]);
	}

	memset(hNor->cfiData, 0x0, sizeof(hNor->cfiData));
	status = NOR_readCFI(hNor);
	if(CSL_SOK != status)
	{
		printf("READ CFI: Bad Status\n");
	}

	return status;
}

问题：

没有添加nor_flash_init();函数时，程序运行正常，能够进入两个PRD函数；

添加nor_flash_init();函数后，无法进入RPD函数，在CCS中调试查看寄存器，全局中断已经使能，定时器中断已经使能。

为什么会这样？SDRAM和NorFlash使用有冲突吗？